When is the best time to observe HIP 104539?

HIP 104539 is best observed from July through September, with peak visibility during August when it transits around midnight in the Northern Hemisphere.

Where is HIP 104539 located in the sky?

HIP 104539 lies in the constellation Vulpecula at right ascension 21h 11m and declination +22° 27′.

What telescope do I need to split HIP 104539?

Splitting HIP 104539 requires an aperture of roughly 60 mm or larger — the components are separated by about 18.1″ at magnitudes near 6.7. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 104539 — Double Star in Vulpecula

Magnitude 6.7^m DoubleStar Vulpecula (Vul) Visible

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Observe

1Physical Properties

Magnitude 6.68

Spectral Type A1V

Star Color White (B-V 0.03)

2Position & Identifiers

RA 21h 10m 32.0s

Dec +22° 27' 17.0"

Constellation Vulpecula (Vul)

HR 8101

HIP 104539

HD 201671

SAO 89505

Double Cat 14710

SIMBAD

3How easy to split?

Primary 6.7 mag Companion 7.4 mag Separation 18.1″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Easy
150 mm Newton 150mm Newt.	Easy	Easy	Easy
Celestron C8 (203 mm SCT) C8 203mm	Easy	Easy	Easy

Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

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Best season Jul – Sep (peak: Aug)

5Multiple Star System

Separation 18.1″

Companion Mag 7.4

Position Angle 301°

Star Colors A: White B: Yellow-white

Discoverer STF2769

Notes

Fixed. Companion A4V.

Separation over time

Measured 1825 → 2020 (195 y)

Separation drift 17.7" → 18.1" (+0.40")

Rate +0.0021" / y

PA drift 301° → 301° (+0°, +0.000°/y)

Essentially fixed on human timescales — the same view your grandchildren will see.

Measured from the WDS observational archive. No orbital solution has been derived — most likely the period is too long to fit an orbit to the available measurement arc.